In summary, fibre optic cables do not use electricity to transmit data; they use light signals. Because fiber lines don't carry electricity, your ONT (Optical Network Terminal), router, and WiFi equipment need to be powered. This is a crucial distinction that often leads to confusion. The light signals are the data. Electronic devices used to generate the light signals being carried by fibre optic cables, such as lasers or LED transmitters, require electricity. Can fiber optics bend and still transmit light? What about fiber optics? To the center of each strand of fiber optic glass is the 'core', which is the. Known as fiber optic cables they are commonly used in the aerospace, telecommunications and medical industries. They serve as the pathways for data.